Prevalence, predictors, and prognosis of serious infections in Takayasu arteritis - a cohort study.

OBJECTIVE: To describe the incidence, risk factors, and outcomes associated with serious infections in patients with Takayasu arteritis (TAK). METHODS: Serious infections (defined as infections resulting in hospitalization or death or unusual infections like tuberculosis) were identified from a cohort of patients with TAK. Corticosteroids and disease-modifying anti-rheumatic drug (DMARD) use at the time of serious infection was noted. Demographic characteristics, clinical presentation, angiography, and disease activity at presentation and the use of DMARDs during follow-up were compared between patients with TAK with or without serious infections. Mortality in patients with TAK who developed serious infections was compared with those without was compared using hazard ratios (HR, with 95%CI). RESULTS: Of 238 patients with TAK, 38 (15.97%) had developed serious infections (50 episodes, multiple episodes in 8, three episodes resulted in death). Among the 38 initial episodes, 11/38 occurred in those not on corticosteroids and 14/38 in those not on DMARDs. Pneumonia (n=19) was the most common infection, followed by tuberculosis (n=12). Patients with TAK who developed serious infections vs those without had higher disease activity at presentation (active disease 97.37% vs 69.50%, ITAS2010 12.66±7.29 vs 10.16±7.02, DEI.TAK 11.21± 6.14 vs 8.76±6.07) and more frequently were initiated on corticosteroids or DMARDs. Hazard ratios calculated using exponential parametric regression survival-time model revealed increased mortality rate in patients with TAK who developed serious infections (HR 5.52, 95%CI 1.75-17.39). CONCLUSION: Serious infections, which occurred in the absence of immunosuppressive treatment in about one-fifth, were associated with increased mortality in patients with TAK.

Pediatric-onset Takayasu arteritis is associated with greater risk of mortality than adult-onset Takayasu arteritis-A systematic review with meta-analysis of observational cohort studies.

A subset of Takayasu arteritis (TAK) has onset in the pediatric age group (≤18 years). The differences in mortality between pediatric-onset and adult-onset TAK are unclear. Therefore, we undertook a systematic review with meta-analysis to compare mortality risk in pediatric-onset with adult-onset TAK. Scopus, Pubmed (MEDLINE and Pubmed Central), recent conference abstracts, clinicaltrials.gov, and the Cochrane database were searched up to August 2023 for relevant studies. Five studies (all of moderate or high quality on the Newcastle Ottawa scale) were identified which had compared mortality between 151 pediatric-onset and 499 adult-onset TAK. Pediatric-onset TAK was associated with a significantly higher risk of death than adult-onset TAK (pooled risk ratio 2.27, 95% confidence interval 1.05 - 4.85, I2=0%). Cardiovascular disease and infections were the major causes of death in both pediatric-onset and adult-onset TAK. Sub-group analyses identified a greater mortality risk with pediatric-onset TAK in retrospective (but not prospective) studies and in studies of high quality (but not in those of moderate quality). Meta-regression did not reveal a significant influence of differences in sex distribution or age or the proportions of patients with pediatric-onset or adult-onset TAK on the pooled mortality risk. An increased mortality risk with pediatric-onset TAK on meta-analysis is consistent with more frequent severe organ manifestations of pediatric-onset TAK (heart failure, renal failure) when compared with adult-onset TAK. Future studies should systematically evaluate differences in the pathogenesis between pediatric-onset and adult-onset to understand the reasons for such observed differences in the mortality risk.

Renal artery involvement is associated with increased morbidity but not mortality in Takayasu arteritis: a matched cohort study of 215 patients.

BACKGROUND: We analyzed differences in presentation and survival of Takayasu arteritis (TAK) with or without renal artery involvement (RAI) from a large monocentric cohort of patients with TAK. METHODS: Clinical and angiographic features were compared between TAK with versus without RAI, with bilateral versus unilateral RAI, and with bilateral RAI versus without RAI using multivariable-adjusted logistic regression. Inter-group differences in survival were analyzed [hazard ratios (HR) with 95% confidence intervals (95%CI)] adjusted for gender, age at disease onset, diagnostic delay, baseline disease activity, and significant clinical/angiographic inter-group differences after multivariable-adjustment/propensity score matching (PSM). RESULTS: Of 215 TAK, 117(54.42%) had RAI [66(56.41%) bilateral]. TAK with RAI or with bilateral RAI had earlier disease onset than without RAI (p < 0.001). Chronic renal failure (CRF) was exclusively seen in TAK with RAI. TAK with RAI (vs without RAI) had more frequent hypertension (p = 0.001), heart failure (p = 0.047), abdominal aorta (p = 0.001) or superior mesenteric artery involvement (p = 0.018). TAK with bilateral RAI (vs unilateral RAI) more often had hypertension (p = 0.011) and blurring of vision (p = 0.049). TAK with bilateral RAI (vs without RAI) more frequently had hypertension (p = 0.002), heart failure (p = 0.036), abdominal aorta (p < 0.001), superior mesenteric artery (p = 0.002), or left subclavian artery involvement (p = 0.041). Despite higher morbidity (hypertension, CRF), mortality risk was not increased with RAI vs without RAI (HR 2.32, 95%CI 0.61-8.78), with bilateral RAI vs unilateral RAI (HR 2.65, 95%CI 0.52-13.42) or without RAI (HR 3.16, 95%CI 0.79-12.70) even after multivariable adjustment or PSM. CONCLUSION: RAI is associated with increased morbidity (CRF, hypertension, heart failure) but does not adversely affect survival in TAK. Key Points •Renal artery involvement in TAK is associated with chronic renal failure. •TAK with renal artery involvement more often have heart failure and hypertension. •Bilateral renal artery involvement (compared with unilateral) is more often associated with hypertension and visual symptoms. •Renal artery involvement is not associated with an increased risk of mortality in TAK.

Increased mortality rate in Takayasu arteritis is largely driven by cardiovascular disease-a cohort study.

OBJECTIVES: To analyze the risk, causes, and predictors of mortality in Takayasu arteritis (TAK). METHODS: Survival was assessed in a cohort of patients with TAK using Kaplan-Meier curves. Age- and sex-standardized mortality ratio (SMR = observed: expected deaths) for TAK were calculated by applying age- and sex-specific mortality rates for the local population to calculate expected deaths. Hazard ratios (HR with 95%CI) for predictors of mortality based on demographic characteristics, presenting features, baseline angiographic involvement, disease activity, number of immunosuppressive medications used, procedures related to TAK, and any serious infection were calculated using Cox regression or exponential parametric regression models. RESULTS: Among 224 patients with TAK (159 females, mean follow-up duration 44.36 months), survival at 1, 2, 5, and 10 years was 97.34%, 96.05%, 93.93%, and 89.23%, respectively. Twelve deaths were observed, most of which were due to cardiovascular disease (heart failure, myocardial infarction, stroke). Mortality risk was significantly higher with TAK (SMR 17.29, 95%CI 8.95-30.11) than the general population. Earlier age at disease onset (HR 0.90, 95%CI 0.83-0.98; or pediatric-onset vs adult-onset disease, HR 5.51, 95%CI 1.57-19.32), higher disease activity scores (ITAS2010: HR 1.15, 95%CI 1.05-1.25, DEI.TAK: HR 1.18, 95%CI 1.08-1.29), any serious infections (HR 5.43, 95%CI 1.72-17.12), heart failure (HR 7.83, 95%CI 2.17-28.16), or coeliac trunk involvement at baseline (HR 4.01, 95%CI 1.26-12.75) were associated with elevated mortality risk. CONCLUSION: Patients with TAK had an elevated risk of mortality as compared with the general population. Cardiovascular disease was the leading cause of death in TAK.

Clinical metabolomics by NMR revealed serum metabolic signatures for differentiating sarcoidosis from tuberculosis.

BACKGROUND: Pulmonary sarcoidosis (SAR) and tuberculosis (TB) are two granulomatous lung-diseases and often pose a diagnostic challenge to a treating physicians. OBJECTIVE: The present study aims to explore the diagnostic potential of NMR based serum metabolomics approach to differentiate SAR from TB. MATERIALS AND METHOD: The blood samples were obtained from three study groups: SAR (N = 35), TB (N = 28) and healthy normal subjects (NC, N = 56) and their serum metabolic profiles were measured using 1D 1H CPMG (Carr-Purcell-Meiboom-Gill) NMR spectra recorded at 800 MHz NMR spectrometer. The quantitative metabolic profiles were compared employing a combination of univariate and multivariate statistical analysis methods and evaluated for their diagnostic potential using receiver operating characteristic (ROC) curve analysis. RESULTS: Compared to SAR, the sera of TB patients were characterized by (a) elevated levels of lactate, acetate, 3-hydroxybutyrate (3HB), glutamate and succinate (b) decreased levels of glucose, citrate, pyruvate, glutamine, and several lipid and membrane metabolites (such as very-low/low density lipoproteins (VLDL/LDL), polyunsaturated fatty acids, etc.). CONCLUSION: The metabolic disturbances not only found to be well in concordance with various previous reports, these further demonstrated very high sensitivity and specificity to distinguish SAR from TB patients suggesting serum metabolomics analysis can serve as surrogate method in the diagnosis and clinical management of SAR.

It's Not All About the Journal Impact Factor.

We read with great interest the recent Panorama article that discussed the rise in the Journal Impact Factor (JIF) of rheumatology journals and the potential effect of the coronavirus disease 19 (COVID-19) pandemic in this rise.1 Although there has definitely been a rise in the JIF of journals following the COVID-19 pandemic, there are concerns about some aspects of the paper that we wish to discuss in this letter.2.

Artificial intelligence-based preventive, personalized and precision medicine for cardiovascular disease/stroke risk assessment in rheumatoid arthritis patients: a narrative review.

The challenges associated with diagnosing and treating cardiovascular disease (CVD)/Stroke in Rheumatoid arthritis (RA) arise from the delayed onset of symptoms. Existing clinical risk scores are inadequate in predicting cardiac events, and conventional risk factors alone do not accurately classify many individuals at risk. Several CVD biomarkers consider the multiple pathways involved in the development of atherosclerosis, which is the primary cause of CVD/Stroke in RA. To enhance the accuracy of CVD/Stroke risk assessment in the RA framework, a proposed approach involves combining genomic-based biomarkers (GBBM) derived from plasma and/or serum samples with innovative non-invasive radiomic-based biomarkers (RBBM), such as measurements of synovial fluid, plaque area, and plaque burden. This review presents two hypotheses: (i) RBBM and GBBM biomarkers exhibit a significant correlation and can precisely detect the severity of CVD/Stroke in RA patients. (ii) Artificial Intelligence (AI)-based preventive, precision, and personalized (aiP3) CVD/Stroke risk AtheroEdge™ model (AtheroPoint™, CA, USA) that utilizes deep learning (DL) to accurately classify the risk of CVD/stroke in RA framework. The authors conducted a comprehensive search using the PRISMA technique, identifying 153 studies that assessed the features/biomarkers of RBBM and GBBM for CVD/Stroke. The study demonstrates how DL models can be integrated into the AtheroEdge™-aiP3 framework to determine the risk of CVD/Stroke in RA patients. The findings of this review suggest that the combination of RBBM with GBBM introduces a new dimension to the assessment of CVD/Stroke risk in the RA framework. Synovial fluid levels that are higher than normal lead to an increase in the plaque burden. Additionally, the review provides recommendations for novel, unbiased, and pruned DL algorithms that can predict CVD/Stroke risk within a RA framework that is preventive, precise, and personalized.

Paediatric-onset Takayasu's arteritis associates with worse survival than adult-onset Takayasu's arteritis. A matched retrospective cohort study.

OBJECTIVES: A subset of Takayasu's arteritis (TAK) begins in the paediatric age group (≤18 years). Differences in prognosis between paediatric-onset and adult-onset TAK are unclear. We compared the differences in the presentation and survival between paediatric-onset and adult-onset TAK in our cohort of TAK. METHODS: From a retrospective cohort of TAK, clinical presentation, angiographic features, treatments received, disease activity, and survival were compared between paediatric-onset and adult-onset TAK. Multivariable-adjusted logistic regression models were used to compute adjusted odds ratio (aOR) with 95% confidence intervals (95%CI) for paediatric-onset vs. adult-onset TAK. Hazard ratios (HR, with 95%CI) for mortality with paediatric-onset vs adult-onset TAK (crude, adjusted for prognostic covariates or differences in presentation) and propensity score-matched survival analyses were estimated. RESULTS: Among 56 paediatric-onset and 135 adult-onset TAK, chest pain (aOR 3.21, 95%CI 1.06-9.74), heart failure (aOR 3.16, 95%CI 1.05-9.53), headache (aOR 2.60, 95%CI 1.01-6.74), ascending aorta (aOR 3.02, 95%CI 1.04-8.80) and left renal artery involvement (aOR 2.45, 95%CI 1.04-5.80) were more frequent in paediatric-onset TAK. Despite similar longitudinal patterns of disease activity and glucocorticoid or disease-modifying antirheumatic drug (DMARD) use, mortality was higher for paediatric-onset TAK (HR, unadjusted 6.13, 95%CI 1.51-24.91; adjusted for prognostic covariates gender, diagnostic delay, baseline disease activity, number of conventional and biologic/targeted synthetic DMARDs used, 4.97, 95%CI 1.20-20.58; adjusted for differences between groups 5.54, 95%CI 1.22-25.09; after propensity-score matching for prognostic covariates, 54 pairs, log-rank p-value 0.026). CONCLUSIONS: Considering the greater mortality risk, greater vigilance is required while managing paediatric-onset TAK.

Overlap syndrome of anti-aquaporin 4 positive neuromyelitis optica spectrum disorder and primary Sjögren's syndrome: a systematic review of individual patient data.

Central nervous system (CNS) involvement can occur in primary Sjögren's syndrome (pSS) due to co-existing neuromyelitis optica spectrum disorder (NMOSD) which has a highly relapsing course requiring indefinite immunosuppression, and if not diagnosed early, damage accrual occurs over time leading to permanent disability and morbidity. In this review, we describe and outline the clinical course and outcomes of anti-aquaporin 4 (AQP4) antibody seropositive NMOSD with pSS overlap cases. To investigate the co-existence of AQP4 + NMOSD with pSS, we conducted a review of individual patient data from case reports and case series found in major databases. The study extracted clinico-demographic features, imaging and laboratory profiles, treatment approaches, and outcomes of these patients. Inclusion criteria for the review required patients to have positivity for anti-AQP4 or NMO-IgG autoantibodies in the blood and/or cerebrospinal fluid (CSF) and exhibit at least one manifestation of both pSS and NMOSD. In this overlap between AQP4 + NMOSD and pSS, 44 patients were included of whom 41 (93.2%) were females. The mean age of pSS onset was 44.8 ± 18.4 years and NMOSD onset was 43.2 ± 19.8 years. In 20 (45.5%) patients, NMOSD preceded pSS onset, 13 (29.5%) NMOSD occurred after pSS onset, and 11 (25%) patients had a simultaneous presentation. 31 (70.5%) patients experienced acute transverse myelitis, 21 (47.7%) optic neuritis, 14 (31.8%) cerebral syndrome, 10 (22.7%) acute brainstem syndrome, 5 (11.4%) area postrema syndrome, and 2 (4.5%) diencephalic clinical syndromes. For the treatment of acute phase, 40 (90.9%) patients received intravenous methylprednisolone, 15 (34.1%) received plasma exchange, and 10 (22.7%) received intravenous immunoglobulin; and for the induction/maintenance therapy, 16 (36.4%) patients received cyclophosphamide, 6 (13.6%) received rituximab, 16 (36.4%) received azathioprine, and 10 (22.7%) received mycophenolate mofetil. Disease course was monophasic in 2 (4.5%) and relapsing in 27 (61.4%) patients. At median (IQR) follow-up duration of 2.4 (6) years, 39 (88.6%) patients showed improvement, 3 (6.8%) showed stabilization and 2 (4.5%) showed worsening of their NMOSD manifestations. In this overlap syndrome of AQP4 + NMOSD and pSS, patients have a neurologically disabling disorder that can mimic neurological manifestations of pSS, frequently occurs prior to the onset of pSS, has a relapsing course, responds well to immunosuppressants, and necessitates indefinite treatment. Collaborative multicentre studies are needed to clarify the natural history and outcomes of this rare overlap syndrome.

Overlap syndrome of anti-aquaporin-4 positive neuromyelitis optica spectrum disorder and systemic lupus erythematosus: A systematic review of individual patient data.

BACKGROUND: Neurological involvement can occur in systemic lupus erythematosus (SLE) due to co-existing neuromyelitis optica spectrum disorder (NMOSD). The symptoms can mimic those of neuropsychiatric manifestations of SLE. Pathogenic anti-aquaporin-4 (AQP4) antibodies, commonly found in NMOSD, are responsible for the neuroinflammatory response and secondary demyelinating lesions. These anti-AQP4 antibodies can be the drivers of neuroinflammatory process in SLE patients, which is distinct from the immunopathogenesis seen in traditional neuropsychiatric SLE. The clinical course is often a relapsing one and is managed differently. In this review, we describe and outline the clinical course and outcomes of AQP4+ NMOSD/SLE overlap cases. METHODS: To investigate the co-existence of SLE with AQP4+NMOSD, we conducted a systematic review of individual patient data from case reports and case series reported in major databases. The study extracted clinic-demographic features, imaging and laboratory profiles, treatment approaches, and outcomes of these patients. Inclusion criteria for the review required patients to have positivity for AQP4 or NMO in the blood and/or cerebrospinal fluid (CSF) and exhibit at least one manifestation of both NMOSD and SLE. RESULTS: In this overlap between SLE and AQP4+NMOSD, a high female preponderance was observed, with 42 out of 46 patients (91.3%) being female. Nearly half of the NMOSD cases (47.8%) had onset after lupus, with a median of 5 years between the two diagnoses. Hematological manifestations were seen in the majority of patients (63%), as well as longitudinally extensive transverse myelitis (87%), and brainstem involvement on imaging (29.6%). Cerebrospinal fluid analysis showed a dominantly lymphocytic pleocytosis, with oligoclonal bands being reported scarcely. Although cyclophosphamide was the most common steroid sparing agent used for maintenance, robust evidence for both efficacy and safety in AQP4+NMOSD is available for mycophenolate mofetil, azathioprine, and rituximab. The majority of reported cases showed a relapsing course, while one patient had a monophasic course. CONCLUSION: AQP4+NMOSD in SLE patients is a relapsing and neurologically disabling disorder that can mimic neuropsychiatric manifestations, frequently occurs after the onset of lupus or may predate, responds to immunosuppressants, and necessitates indefinite treatment.

Cardiovascular risk in vasculitis.

The present review summarizes the burden, risk factors, biomarkers of and therapeutic consideration for cardiovascular disease in systemic vasculitis. Ischemic heart disease (IHD) and stroke are intrinsic features of Kawasaki disease, Takayasu arteritis, Giant Cell Arteritis (GCA), and Behcet's disease. The risk of IHD and stroke is increased in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) and cryoglobulinemic vasculitis. Behcet's disease could present with venous thromboembolism. The risk of venous thromboembolism is increased in AAV, polyarteritis nodosa, and GCA. The risk of cardiovascular events is greatest at or immediately after the diagnosis of AAV or GCA, therefore, controlling vasculitis disease activity is of utmost importance. Traditional as well as disease-related risk factors drive the heightened cardiovascular risk in vasculitis. Aspirin or statins reduce the risk of IHD or stroke in GCA or the risk of IHD in Kawasaki Disease. Venous thromboembolism in Behcet's disease should be treated with immunosuppressive therapy rather than with anticoagulation.

Arterial wall fibrosis in Takayasu arteritis and its potential for therapeutic modulation.

Arterial wall damage in Takayasu arteritis (TAK) can progress despite immunosuppressive therapy. Vascular fibrosis is more prominent in TAK than in giant cell arteritis (GCA). The inflamed arterial wall in TAK is infiltrated by M1 macrophages [which secrete interleukin-6 (IL-6)], which transition to M2 macrophages once the inflammation settles. M2 macrophages secrete transforming growth factor beta (TGF-ß) and glycoprotein non-metastatic melanoma protein B (GPNMB), both of which can activate fibroblasts in the arterial wall adventitia. Mast cells in the arterial wall of TAK also activate resting adventitial fibroblasts. Th17 lymphocytes play a role in both TAK and GCA. Sub-populations of Th17 lymphocytes, Th17.1 lymphocytes [which secrete interferon gamma (IFN-γ) in addition to interleukin-17 (IL-17)] and programmed cell death 1 (PD1)-expressing Th17 (which secrete TGF-ß), have been described in TAK but not in GCA. IL-6 and IL-17 also drive fibroblast activation in the arterial wall. The Th17 and Th1 lymphocytes in TAK demonstrate an activation of mammalian target organ of rapamycin 1 (mTORC1) driven by Notch-1 upregulation. A recent study reported that the enhanced liver fibrosis score (derived from serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and pro-collagen III amino-terminal pro-peptide) had a moderate-to-strong correlation with clinically assessed and angiographically assessed vascular damage. In vitro experiments suggest the potential to target arterial wall fibrosis in TAK with leflunomide, tofacitinib, baricitinib, or mTORC1 inhibitors. Since arterial wall inflammation is followed by fibrosis, a strategy of combining immunosuppressive agents with drugs that have an antifibrotic effect merits exploration in future clinical trials of TAK.

Management of Takayasu arteritis.

This review overviews the challenges in the assessment of disease activity, damage, and therapy of Takayasu arteritis (TAK). Recently developed disease activity scores for TAK are more useful for follow-up visits and require validation of cut-offs for active disease. A validated damage score for TAK is lacking. Computed tomography angiography (CTA), magnetic resonance angiography (MRA), and ultrasound enable the evaluation of vascular anatomy and arterial wall characteristics of TAK. 18-fluorodeoxyglucose (18-FDG) positron emission tomography (PET) visualizes arterial wall metabolic activity and complements the information provided by circulating C-reactive protein (CRP) levels. ESR and CRP alone moderately reflect TAK disease activity. TAK is corticosteroid-responsive but relapses upon tapering corticosteroids. Conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs) are the first-line maintenance agents, and tumor necrosis factor-alpha inhibitors, tocilizumab, or tofacitinib are second-line agents for TAK. Revascularization procedures for TAK should be used judiciously during periods of inactive disease.

Validation of the 2022 American College of Rheumatology/EULAR classification criteria for Takayasu arteritis.

OBJECTIVES: The present study validates the 2022 ACR/European Alliance of Associations for Rheumatology (EULAR) classification criteria for Takayasu's arteritis (TAK), compared with the 1990 ACR TAK classification criteria. METHODS: The fulfilment of 2022 ACR/EULAR and 1990 ACR TAK criteria from four referral centres was assessed for TAK compared with extracranial giant cell arteritis (EC-GCA) and other controls. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio of a positive test (LR+) or negative test (LR-), and area under receiver operating characteristics curve (AUC) were calculated. RESULTS: Among 504 patients with TAK (404 females) and 222 controls (151 females, 144 patients with EC-GCA), the 2022 ACR/EULAR criteria had better sensitivity (95.83% vs 82.94%) and NPV, but poorer specificity (63.51% vs 90.54%), PPV, LR+, LR- and AUC at the pre-determined cut-offs than the 1990 ACR criteria. The 2022 ACR/EULAR criteria had greater specificity (76.06% vs 57.62%) and AUC (0.845 vs 0.771), with similar sensitivity (93% vs 96.53%) in males as in females. The 2022 ACR/EULAR criteria performed similarly with only EC-GCA as controls (sensitivity 95.83%, specificity 60.42%, AUC 0.781). Sensitivity remained similar, whereas specificity was higher for 40-60 years vs <40 years. Cut-offs of ≥6 (sensitivity 91.87%, specificity 82.88%) and ≥7 (sensitivity 86.71%, specificity 86.49%), or removing the point for female sex (sensitivity 92.64%, specificity 81.08%) greatly improved the balance between sensitivity and specificity. CONCLUSION: The poor specificity of the 2022 ACR/EULAR TAK criteria in real-life settings was improved by increasing the cut-off to 6 or 7, or removing the point for female sex.

Metabolic inflammatory volume and total inflammatory glycolysis: novel parameters to evaluate PET-CT disease activity in Takayasu arteritis.

OBJECTIVES: To evaluate diagnostic accuracy for active Takayasu arteritis (TAK) for two novel 18F-fluorodeoxyglucose PET-CT parameters, the inflammatory volume (MIV) and total inflammatory glycolysis (TIG), to quantitate volume of metabolically-active arterial tissue. METHODS: From a cohort of TAK (n = 36, 35 immunosuppressive-naïve), images of PET-CTs were reviewed for mean and maximum standardized uptake value (SUVmean and SUVmax), target-to-blood pool ratio (TBR), target-to-liver ratio (TLR), and PET Vasculitis Activity Score (PETVAS). Regions of interest were drawn to semiautomatically calculate MIV in areas of 18F-fluorodeoxyglucose uptake ≥ 1.5 SUVmean after excluding physiological tracer uptake. TIG was calculated by multiplying MIV with SUVmean. PET-CT parameters, ESR, CRP, and clinical disease activity scores were compared against the gold standard of physician global assessment of disease activity (PGA, active/inactive). RESULTS: Using dichotomized cut-offs for active TAK at SUVmax (≥ 2.21), SUVmean (≥ 1.58), TBR (≥ 2.31), TLR (≥ 1.22), PETVAS (various cut-offs), ESR (≥ 40 mm/hour), and CRP (≥ 6 mg/L), the novel indices MIV (≥ 1.8) and TIG (≥ 2.7) performed similar [area under the receiver operating characteristics curve (AUC) 0.873 for both] to SUVmax (AUC 0.841) and SUVmean (AUC 0.851), and better than TBR (AUC 0.773), TLR (AUC 0.773), PETVAS [≥ 5.5 (AUC 0.750), ≥ 10 (AUC 0.636), ≥ 15 (AUC 0.546)], ESR (AUC 0.748), or CRP (AUC 0.731). MIV and TIG had similar agreement with PGA or CRP as with SUVmax or SUVmean, and better agreement than TBR, TLR, or PETVAS cut-offs. CONCLUSIONS: MIV and TIG performed similarly, therefore, are viable alternatives to existing PET-CT parameters to assess TAK disease activity in this preliminary report. Key Points • MIV and TIG performed similar to SUVmax and SUVmax for disease activity assessment in TAK. • MIV and TIG distinguished active TAK better than TBR, TLR, PETVAS cut-offs, ESR, or CRP. • MIV and TIG had better agreement with PGA or CRP than TBR, TLR, or PETVAS cut-offs.